FORREST CITY, Ark. -- Three people were killed when a Texas-bound bus collided with a pick-up truck and then was hit by a tractor trailer on Interstate 40 in Arkansas.

More than 40 people were injured when the westbound bus carrying 44 passengers crossed the median near Forrest City, Ark., WPTY-TV, Memphis, reported.

The dead included the driver of the pick-up truck and two bus passengers, while the bus and tractor-trailer drivers sustained minor injuries in the crash about 40 miles west of Memphis, the report said.

Investigators were not immediately able to determine why the Tornado Bus Line vehicle crossed the median around 10 p.m., and state troopers closed the highway into Monday morning to investigate, WMC-TV, Memphis, reported.

The bus reportedly first hit the pick-up truck head-on, spun, and then was hit broadside by the tractor-trailer, CNN said.